In the past, little attention was paid to the storage or recycling of refrigerant. When refrigeration systems were being repaired or when the refrigerant, such as those sold under the trademark "Freon", was contaminated sufficiently to affect the effectiveness of refrigeration, the refrigerant was vented into the atmosphere.
Recent developments have, however, created a demand for systems capable of storing refrigerant while at the same time purifying the contaminated refrigerant. Due to the enactment of recent federal and international regulations, it is impermissible to release even small amounts of almost any refrigerant into the atmosphere.
Systems that can retrieve refrigerant, purify and store the refrigerant, and return it to a useable state without any release into the environment will soon be needed by every business that has significant amounts of refrigeration equipment. The present invention relates to modifications and improvements on the refrigerant reclaim method and apparatus as described in co-pending U.S. patent application Ser. No. 07/380,691 of Van Steenburgh, Jr.
U.S. patent application Ser. No. 380,691, discloses an apparatus for drawing refrigerant from a container, or a refrigeration system to be repaired, heating the refrigerant sufficiently to maintain it in a gaseous state while it passes through an oil separator into the intake of a compressor. Compressed gaseous refrigerant is discharged from the compressor and passed through a heat exchanger to heat the incoming liquid refrigerant and then passes through to a condenser where its liquification is completed. Generally some condensation of the gaseous refrigerant will occur in the heat exchange means, and in some stages of operation the gaseous refrigerant will be completely liquified before introduction into the condenser. The condenser acts as a back up to the heat exchanger means to assure total liquification under all conditions.
The liquified refrigerant is passed from the condenser into a chill tank. Liquified refrigerant is removed from the bottom of the chill tank and passed through a filter-dryer and an expansion device to again vaporize the refrigerant. The gaseous refrigerant is then passed through a coil submerged in the liquid refrigerant in the chill tank. The temperature of the liquid refrigerant is lowered by the chilling effect of the expanding gaseous refrigerant passed in a thermally conductive path through the chill tank. The gaseous refrigerant is then introduced into the inlet of the compressor, where it is compressed and passed through the heat exchanger and the condenser and back to the chill tank.
The refrigerant can be repeatedly passed from the chill tank through the filter-dryer, expansion device, cooling coil, compressor, heat exchanger, condenser and back to the chill tank. This repeated process will progressively lower the temperature of refrigerant in the chill tank, increase the refrigerant purity by repeated passing through the filter-dryer, and, by lowering the temperature of the refrigerant, maximize the separation of air from the refrigerant.
One drawback of the device described in application Ser. No. 380,691 is the size and weight of the entire system. As described and with the preferred components, the completed system is also relatively expensive. A device that combines the operational performance characteristics of the device described in the application Ser. No. 380,691 yet has a lower price, is lighter and smaller would be a great improvement and would find a large market.
U.S. patent application Ser. No. 309,421 describes several improvements to the system described in the application Ser. No. 380,691. One of these improvements is the inclusion of an oil accumulator device in-line with the compressor of the basic refrigeration reclaim system. The oil accumulator serves several functions in the refrigerant reclaim system. One function, is to remove any residual oil in the incoming contaminated refrigerant that has gotten past the main oil separator.
The primary function of the oil accumulator, however, is the removal of oil from the refrigerant that originates from the compressor, and the return of this oil to the compressor. In a piston-type compressor, with every stroke of the piston a very small amount of oil--which of necessity must be present in the piston chamber--leaves the compressor with the compressed refrigerant. Over time and with repeated expansion/chilling cycles, the compressor will continually lose oil to the refrigerant. The oil accumulator acts to remove this residual oil from the refrigerant and return it to the compressor. The end result is a refrigerant containing a minimal amount of oil, and a greatly reduced oil loss from the compressor. The undetected loss of oil from compressors is one of the major causes of refrigerant reclaim system breakdowns.